1. Field of the Invention
The present disclosure relates to a disk drive device including a fluid dynamic bearing mechanism.
2. Description of the Related Art
Recently, disk drive devices like hard disk drives are generally built with a fluid dynamic bearing mechanism that enables a stable and fast-speed rotation of a disk. For example, JP 2008-275074 A discloses a motor including a dynamic pressure bearing, and this motor has a lubricant filled between a sleeve forming apart of a stator and a shaft forming a part of a rotor. Dynamic pressure generated by the lubricant supports the rotor in a non-contact manner, enabling a smooth and fast-speed rotation.
Conversely, there is a demand for disk drive devices to further increase a large recording capacity. In order to satisfy such a demand, a recording density can be increased.
To increase the recording density, a gap between a recording/playing head and a disk surface can be reduced. When, however, this gap is too narrow, if slight particles stick to the disk surface, it becomes difficult for the recording/playing head to precisely trace tracks on the disk, resulting in a read/write failure. In the worst case, the recording/playing head is damaged, resulting in a malfunction of the disk drive devices.
One of the causes of such particles is vaporization of the lubricant in the fluid dynamic bearing mechanism due to a high-temperature environment inherent to a fast-speed rotation of the disk, i.e., a fast-speed rotation of the motor. The vaporized lubricant diffuses the interior of the disk drive devices, and is deposited on the disk surface, thereby forming a condensation.
As to the high-temperature environment, the temperature of the usage atmosphere of the disk drive devices is increasing due to downsizing, and there is a demand to enable the use of the disk drive devices at a further higher temperature, e.g., an atmosphere temperature of equal to or higher than 85 degrees.
Still further, there is also a demand to increase a time until the lubricant is vaporized and dissipated, e.g., to ensure a longer product lifetime of equal to or longer than five years.
Concurrently, the disk drive devices are often built in portable electric devices recently, and there is a demand for thinning in such a case. In general, when the disk drive devices are made thin, the strength of the disk drive devices is reduced.
Therefore, the present disclosure has been made in view of the aforementioned circumstances, and it is an objective of the present disclosure to provide a disk drive device which can address the technical problem originating from thinning, while at the same time, can further increase a large recording capacity.